One night three months ago, Rosa Castro finished her dinner, opened her laptop, and uncovered a novel object that was neither planet nor star. Therapist by day and amateur astronomer by night, Castro joined the NASA-funded Backyard Worlds: Planet 9 citizen science project when it began in February — not knowing she would become one of four volunteers to help identify the project's first brown dwarf, formally known as WISEA J110125.95+540052.8.After devoting hours to skimming online, publicly available "flipbooks" containing time-lapse images, she spotted a moving object unlike any other. The search process involves fixating on countless colorful dots, she explained. When an object is different, it simply stands out. Castro, who describes herself as extremely detail oriented, has contributed nearly 100 classifications to this specific project.A paper about the new brown dwarf was published on May 24 in The Astrophysical Journal Letters. Four citizen scientists are co-authors of the paper, including Castro. Since then, Backyard Worlds: Planet 9 has identified roughly 117 additional brown dwarf candidates.The collaboration was inspired by the recently proposed ninth planet, possibly orbiting at the fringes of our solar system beyond Pluto."We realized we could do a much better job identifying Planet Nine if we ...